My Brake pedal makes a humming when pressed

Brakes work as they should but a humming sound comes from the engine area

My car has 190000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
The brake caliper(s) could be failing to retract, thus setting up a harmonic during or after application of the brakes. Calipers should be rebuilt (or replaced) every 75,000 miles or so due to the harsh operating conditions they endure, principally high heat and corrosion. The problem is brake calipers eventually become sticky in operation. In addition, the caliper torque plate has sliding pins that have to be free and well lubricated with high temperature brake grease in order for the brake pads to retract from the rotor once you release the brake pedal. There are also brake shims in the assembly that could have failed or are missing. Rotor defects or wear can also cause brake noise. These possibilities should be looked at first. To resolve this, the recommended service is a brake noise diagnostic. If you request that diagnostic, a certified mechanic will be dispatched by YourMechanic to evaluate your brakes and address all your concerns.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

If the humming noise is a high pitched hum, or more of a consistent squeaking sound, it`s possible that it is caused by a build-up of brake dust on the brake rotors. In most cases, this is not a cause for concern, however, it could also indicate that your brake pads are low and about time for replacement.
The most common would be a failing tire, wheel balance, wheel bearing, dragging brake pad, sticking caliper, or a CV axle issue. A qualified technician, such as one from YourMechanic, will be able to diagnose your humming noise and perform any repairs required to get the car back to normal.
Worn brake pads: Over time, brake pads wear down due to regular wear and tear. When your car`s brake pads need changing, they`ll squeak when you press down on them. You should have your brake pads replaced as soon as you hear them squeak.
Your Braking System Needs Lubrication

Without proper lubrication, there can be a grinding noise from your car`s brakes that is caused by the caliper bolts. The caliper bolts keep the brake calipers securely in place. However, over time they may begin to rust, which causes the grinding sound.

If the caliper or caliper pistons become stuck, it is unable to properly squeeze the brake pads against the rotors, which may cause you to feel some vibrations when you hit the brakes.
WD-40 Specialist Automotive Brake and Parts Cleaner is safe to use on clutch and brake assemblies, brake discs, callipers, brake drums, brake pads and brake linings.
Sticking caliper or wheel cylinder: A sticking caliper can cause the pads to be continuously forced against the rotor, creating a grinding or squealing noise. The same is true for a wheel cylinder that`s stuck, forcing the shoes against the drums.
In many cases, a sticking brake caliper can be easily identified by the abnormal sounds that it produces. This most notably includes grinding and scraping noises that result from rapid or abnormal brake pad wear.
1) Your pedal vibrated because the ABS (anti-lock braking system) was activated. If the pedal vibrations (pulsing and groaning noises, too) happened when you e-braked, chances are ABS was activated. ABS prevents your tyres from locking up, which could lead to an uncontrollable skid.
Brake pads that are worn, damaged, or warped, may cause vibrations along with a squeaking sound that indicates brake pads require replacement. Similarly, brake pads that are soiled from dirt, oil, or other toxins can cause vibrations as they attempt to grasp the rotor.
Damaged Brake Caliper

Braking produces extensive heat as it relies on friction. The produced heat may damage the brake calipers that become corroded and affect the fluid pressure, thus causing soft and spongy brakes.

The cup seals or the cylinder bore may be worn. Any time that the brake pedal of a vehicle is fading towards the floor, internal leaking or cup seals being bypassed must be considered. A fading pedal that has no external leak is one of the most common master cylinder symptoms caused by the cup seals.
The spray will be safe for your calipers, pads and rotors, so you can apply it liberally to all these components. A warning, though: Brake cleaner is not something you just want to spray around like air freshener. Some brake cleaners contain caustic chemicals, and some are highly flammable.
Get ready to scrub

Moisten the caliper with water and then spray on some brake cleaner and allow it to dwell for a minute or so. The cleaner will penetrate and loosen dirt and contamination. Be accurate when spraying cleaner on the brake caliper, as you don`t want to be overspraying on to the brake discs and fork legs.

Silicone-based brake grease is designed for caliper and wheel cylinder assembly work because silicone is an excellent lubricant for rubber and plastic. It is compatible with all rubber compounds including nitrile, teflon, nylon and other synthetic rubbers.
Super Lube® Silicone Lubricating Brake Grease should be used at every point in the brake system where parts slide or move. With disc brakes, lubrication points include: caliper slides, pins, bushings and contact points where the pads slide within the caliper housing.
Did you know that it is recommended to maintain your brake calipers every 2 years or 24,000 miles on your vehicle? Brake caliper servicing is something that is needed and different from your typical brake service.
If air gets into a brake line, it can produce uneven pressure across the brake calipers and pads, which could make the car shake when you apply the brakes.
If you notice more pedal effort required to generate the same amount of braking pressure, there could be a problem with the ABS control module. Again, brake pedal issues like increased foot effort can mean other things, like worn brake pads or a failing brake booster, so be sure to have your mechanic check everything.
Uneven brake pads: When the brake fluid gets low, the pedals cannot depress brake pads with the same amount of pressure. This causes uneven wear on the pads. In turn, you experience squeaking, squealing, and grinding when you apply the brakes. The vehicle may also rumble and vibrate when you use the brakes.
The biggest reason for this shaking problem is the condition of your rotors – the disc your brake pad clamps down on when you apply your brakes. Most commonly, the vibration happens because the rotors have some kind of imperfection on their surface or they have changed shape (warped) over time.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Supportive bar attached to brake pedal interrupts proper braking process
ANSWER : It’s possible to have someone alter the brake pedal or adapt a brake pedal from a different vehicle. You may call around to some customization shops to see if anyone is interested in taking on the project. But first, I would try reaching out to the selling dealer with your concern – especially since it is a new model. Good luck.

Brake sensor is to sensitive causing brakes to flicker while driving. 2005 Mercury Montego
ANSWER : Hi there – your brake light switch needs a minor adjustment. It is adjusted too "tight" or close to the brake pedal lever, or possibly has failed. Adjusting/replacing it will eliminate this flickering problem. I recommend a brake light isn’t working inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.

Low brake pedal and anti-lock brakes are not kicking in.
ANSWER : The brake pedal is working to stop the vehicle, but there may be air in the controller unit causing the ABS brakes to not function. I recommend bleeding the brake system from the farthest location from the master cylinder to the master cylinder including the ABS unit. If the brakes are still spongy after a full bleed, then the controller will need to be replaced. If you need further assistance with your brake pedal being spongy, then seek out a professional, such as one from Your Mechanic, to help you.

Hard brake pedal and rear brakes locking up.
ANSWER : Hi. I will help you with this issue you are having with your 2001 Durango. Unless you bled the master cylinder, it is possible there is still air in the system. If you car is equipped with ABS, air could have also gotten trapped in the ABS modulator. If ABS equipped, a bi-directional scan tool would be essential to manually activate the ABS system to clear air from that segment of the lines while you are bleeding the system. It is also possible that in all of this work somehow the proportioning valve has been affected causing the desired pressure differential, front versus back, to get out of spec. Using a 2,500 PSI gauge, you can check the pressures at each wheel and that will definitely give you a clue as to which brake circuit is the issue (or both), whether the proportioning valve is working properly and whether the line pressures at each wheel are within spec. Should you need a second opinion, by all means feel free to contact YourMechanic for assistance and we will diagnose and repair the issue for you.

EPC light on 2004 Jetta. Code said brake switch faulty, but brakes lights worked. Replaced brake switch, now no brake lights.
ANSWER : Hi there. The first thing that pops in my mind beyond of what you have listed is perhaps the electrical harness attached to the brake switch. Perhaps the harness itself is damaged or you have an exposed wire, loose ground wire somewhere. You might want to have a professional mobile mechanic come to your location and complete a brake lights not working inspection to help you diagnose this issue.

Driver has to pump brake pedal multiple times to brake
ANSWER : I’m not familiar with a pump assisting the system, but the master cylinder creates the hydraulic pressure needed to transfer power from your floor to the brake assemblies. A failing master cylinder can feel like a leak in the hydraulic system as it cannot create the proper pressure. Have a certified technician, like one from YourMechanic, physically inspect the brake system for any actual leaks as well.

Changed brake master cylinder, bled 10 times, and the pedal is soft The rear brakes are not locked but close. Truck now running rough.
ANSWER : You will have to bleed the brakes from the farthest location all the way to the master cylinder. There is still air in the lines causing the issue. Check the vibrations on the vehicle to see if the engine mounts are damaged or if the brakes are not releasing causing the engine to run harder than normal to overcome the braking force. If you need further assistance with your vehicle’s brake system, then seek out a professional, such as one from Your Mechanic, to help you.

Grumbling sound while breaking at the stop light, brake pedal shakes
ANSWER : You are exactly right. It is your anti-lock braking system that is engaging when you hear that buzzing sound. A number of things could cause the anti-lock braking system to engage when it shouldn’t. Some of these things would include:

air in the brake system
one or more faulty wheel speed sensors
a faulty ABS control module
a faulty ABS pump

I would recommend having your braking system inspected by a technician who is proficient in anti-lock brake repairs. This inspection would cover all the parts listed to determine which one is causing the ABS malfunction.

When the inspection is completed, the mechanic would then relay the diagnostic information over to you to make a repair decision.